Wheel retaining unit



FIG. 1 is a perspective view of a wheel retaining unit showing my new design;

FIG. 2 is a front view thereof; the opposite side being a mirror image of the shown;

FIG. 3 is a left view thereof;

FIG. 4 is a right view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a perspective view illustrating the wheel retaining unit in position of use, and also illustrating environmental structure and other wheel retaining units in broken lines that form no part of the claimed design. 

The ornamental design for a wheel retaining unit, as shown and described. 